Luna/apps/time.cpp

#include <os/ArgumentParser.h>
#include <os/File.h>
#include <os/Process.h>
#include <stdio.h>
#include <sys/resource.h>

Result<int> luna_main(int argc, char** argv)
{
    Vector<StringView> command;

    os::ArgumentParser parser;
    parser.add_description("Time a command.");
    parser.add_system_program_info("time"_sv);
    parser.set_vector_argument(command, "command"_sv, true, true);
    TRY(parser.parse(argc, argv));

    auto pid = TRY(os::Process::fork());

    if (pid == 0)
    {
        TRY(os::Process::exec(command[0], command.slice()));
        unreachable();
    }

    TRY(os::Process::wait(pid, nullptr));

    struct rusage usage;
    if (getrusage(RUSAGE_CHILDREN, &usage) < 0)
    {
        perror("getrusage");
        return 1;
    }

    auto cmdline = TRY(String::join(command, " "));

    os::println("%s  %d.%.2ds user %d.%.2ds system"_sv, cmdline.chars(), usage.ru_utime.tv_sec,
                usage.ru_utime.tv_usec / 10000, usage.ru_stime.tv_sec, usage.ru_stime.tv_usec / 10000);

    return 0;
}